I. Field of the Invention
The present disclosure relates to the field of chemistry. In some aspects, the present disclosure relates to carbonylation reactions and methods of producing carboxylic acids.
II. Description of Related Art
Rhodium catalyzed carbonylation is a widely used process to produce carboxylic acids such as acetic acid. In particular, this process is used commercially to produce glacial acetic acid. Quantum Chemical Company described the use of pentavalent complexes such as tri-substituted phosphine oxides to improve the conversion rate of methyl acetate to acetic acid without the need to introduce high concentrations of water.
The activity of a rhodium carbonylation catalyst is reduced over time as the catalyst tends to precipitate under the carbonylation conditions and leads to decreased activity over time. Addition of ruthenium to the catalytic mixture has been shown to stabilize the rhodium catalyst and increase the carbonylation rate when using a rhodium catalyst. This increased rate has been shown under both high water and low water carbonylation conditions. The incorporation of triphenylphosphine oxide into the carbonylation process has been shown to lead to improved catalytic carbonylation system. Thus, a catalytic system which has an improved conversion rate while stabilizing the rhodium carbonylation catalyst so that it has an increased catalytic lifetime is commercially desirable.